Human chorionic gonadotropin (hCG), also known as pregnancy hormone, is produced by the placenta of the developing child and is detectable in pregnant women's urine and blood. This is the basis for urine pregnancy testing kits and blood hCG levels for pregnancy detection.

When a woman's doctor requests blood hCG levels and compares them to reference values based on the length of her pregnancy, the woman might become confused. Is my hCG level good and does it mean that the baby is growing normally? What if my hCG levels are not as expected? Should I repeat my hCG levels or is one test sufficient? These are some of the questions that frequently cross a woman's mind.

hCG Levels

Here are 10 key details about hCG levels that you should be aware of

1. Should every patient who is pregnant have their hCG levels checked?

NO. A quick urine pregnancy test is all you need to know if you gave birth naturally. However, a blood hCG level can be checked if your urine test is negative and your doctor wants to retest. Urine pregnancy testing kits can miss an early pregnancy when hCG is present, which can be found as early as 11 days after conception.

2. Interpretation of hCG levels in patients undergoing IVF

Congratulations, you are pregnant if your test is positive, but proceed with caution!!

During embryo transfer in IVF, an embryo is inserted into your uterus. After 12โ€“15 days, a blood hCG level test is performed to determine whether or not you have conceived.

A value of more than 100 mIU/ml is regarded as a strong positive result when a day 5 or blastocyst stage embryo has been transferred and hCG levels are tested at least 12โ€“14 days after embryo transfer. A result is considered negative if it is less than 5 mIU/ml. Any value between 5 and 100 mIU/ml is regarded as an intermediate level and should be retested 48 to 72 hours later to check for an increase or decrease in hCG levels.

3. Interpret hCG triggers given during an IVF cycle carefully

Blood levels for hCG after embryo transfer are advised to be checked only after 14 days to determine whether or not implantation has occurred. This is because medications containing hCG that are frequently used in IVF practice as trigger injections may interfere with hCG levels. Additionally, since they frequently produce inaccurate results, one should avoid using online hCG calculators.

4. Increase in the hCG's duration

In a healthy pregnancy, hCG levels will roughly double in 48 to 72 hours and continue steadily rising until they peak at around 12 weeks. After that, hCG levels begin to decline slightly before staying steady until delivery.

5. hCG concentrations either rise or fall.

It doesn't matter if your hCG levels didn't double in 48โ€“72 hours, right?

DO NOT FREAK OUT. Discuss with your doctor and avoid reading too much into the numbers.

It can take up to 96 hours for hCG to double up in up to 15% of healthy pregnancies.

However, a gradual increase in hCG levels may indicate an ectopic pregnancy, which is a pregnancy that has developed in an abnormal place. In this situation, your doctor might advise scheduling an immediate transvaginal ultrasound to confirm the diagnosis.

If a pregnancy is in a normal location but is not progressing well, a slow rise in hCG may also be observed, and such pregnancies may result in a miscarriage. A decrease in hCG levels is undoubtedly a bad sign and may indicate a biochemical pregnancy or an early miscarriage.

6. What difference does extreme low or high hCG make?

The level of HCG there is incredibly low

  • Biochemical pregnancy: This type of pregnancy occurs when, following an initial positive hCG result, there is a decline in hCG levels, indicating that implantation has taken place but that the pregnancy did not progress further.
  • Blighted ovum (pregnancy where the placenta and sac both develop but no embryo is found).
  • Ectopic pregnancy (when a fertilised egg implants and develops outside a woman's womb, which is frequently fatal due to internal bleeding).

Very high level could suggest

  • Molar pregnancy: The placenta develops a tumour and begins secreting excessive amounts of hCG.
  • Multiple pregnancies - Implantation of more than one embryo.

7. To check on my baby's growth, how early can I have an ultrasound done?

Only when hCG levels exceed 1500 mIU/ml can a pregnancy be detected on ultrasound. It is ordinarily planned for 1 month after the embryo transfer or 15 days following a positive hCG test. An ultrasound can detect the baby's heartbeat and confirm the pregnancy's status (normal or abnormal). To rule out an ectopic pregnancy, doctors will occasionally recommend an ultrasound one week early.

8. Do I need something to do with hCG?

The majority of pregnant women experience fluctuating levels of the hormone hCG, which can result in symptoms like increased mood swings, nausea, and vomiting in the early weeks of pregnancy. Due to higher hCG levels compared to singleton pregnancies, this is why women pregnant with twins or triplets experience more nausea and vomiting.

9. Rise in hCG levels in non-pregnant women

Very rarely, some cancers, such as ovarian germ cell tumours and gestational trophoblastic diseases (placental tumours), can cause women who are not pregnant to produce hCG. Certain testicular cancers can even cause men to produce hCG.

10. After delivery or a miscarriage, a positive pregnancy test

After delivery or a miscarriage, hCG levels can remain positive for up to 4-6 weeks. During this time, a urine pregnancy test may produce a false positive result if performed.